At present, a further development of the CD, the so-called DVD ("Digital Video Disc" or "Digital Versatile Disc"), is about to be introduced on the market. The DVD is likewise an optical data medium having the same dimensions as those of the CD, but a considerably higher data storage capacity than the CD. The players for DVDs will in some instances also enable the playing of existing audio CDs.
During the reproduction of a compact disc (CD) by an audio CD player, the EFM (eight-to-fourteen modulation) signal is obtained from the optically scanned signal after pulse shaping. After EFM demodulation, the signal obtained in this way is firstly fed to an error correction circuit prior to outputting by a digital-to-analogue converter. In the error correction circuit, coding of the data at the recording end in accordance with the cross-interleave Reed-Solomon method is reversed. For this purpose, the signal is read into a memory and is read out again in the de-interleaved order. If complete error correction is not possible, then measures for error concealment are additionally taken in order to reduce the audibility of these errors. These error concealment methods implemented in an audio CD player are simple and not always adequate. However, more complicated methods are not used for cost reasons, since they would require a more powerful processor and a larger memory. If the data loss is very great, only the muting of the signal therefore remains in the extreme case.